Floating-bearing motor pump cooled by a circulating fluid

ABSTRACT

The present invention relates to a motor pump ( 10 ) free from bearings, cooler and mechanical sealing, more specifically to a hydraulic motor pump, which comprises a housing ( 14 ) defined by a first chamber ( 19 ) isolated from fluids and a second chamber ( 17 ). In the second chamber ( 17 ) there is an integral rotor/turbine assembly ( 11 ), the rotor and the turbine being induced by magnetic forces of a stator ( 12 ), which is located in the first chamber ( 19 ). A fluid inlet ( 15 ) and a fluid outlet ( 16 ) are located at the same end of the motor pump ( 10 ), so that most of the fluid impelled into the motor pump ( 10 ) is guided directly to the outlet ( 16 ) with the aid of a fluid guide ( 20 ) located at the front end ( 24 ) of the rotor/turbine assembly ( 11 ), enabling an increase in the flowrate inside the motor pump ( 10 ), thus increasing the yield thereof.

The present invention relates to a motor pump, especially a hydraulic motor pump, free from bearings, fan and mechanical sealing, wherein the cooling and the lubrication are made through the fluid itself that is pushed into the motor pump. Besides, the configuration of the motor pump enables an increase in the flow-rate in its interior, thus increasing the yield thereof.

DESCRIPTION OF THE PRIOR ART

Nowadays, there are different models of hydraulic motor pumps, used for impelling fluids. These motor pumps are generally composed by two chambers, the first one comprising a stator and induced rotor, and the second chamber comprising a hydraulic turbine that impels the fluid. However, the fluid present in the second chamber cannot come into contact with first chamber elements, as this contact may cause short-circuits and irreparable damage to the motor pump.

Thus, the motor pump chambers must be isolated from each other, but, in addition to the necessary isolation between the chambers, it is necessary that it is necessary that there is further rotor rotational motion transmission from the rotor. So, for this to be possible, a number of mechanical devices are required, such as rollers, axis, bearing supports, roller bearings, cooling systems, gaskets, among others.

Roller bearings that are usually lubricated by oil or grease, so that there is a reduction of friction and wear between the motor pump parts, have the function of supporting the rotor axis, so that, when the axis is induced by the electromagnetic forces of the stator, it will turn with the aid of the rollers. The rotor, in turn, is connected by one of its axis ends to the hydraulic turbine, which has blades that initiate a rotating motion, impelling the fluid upon induction of the rotor.

However, as the rotor assembly and the stator are in operation, the assembly temperature tends to rise, reaching levels that may affect the operation of the motor pump. So, in order to prevent this, external cooling systems are used, usually coolers, preventing overheating of the motor pump. These coolers are usually connected to the end of the rotor axis, taking advantage of the rotation thereof to carry out the turning movement.

With this type of motor pump, in order to prevent the fluid enters into the motor pump from coming into contact with the stator and the rotor, mechanical sealing means are provided, which isolate hydraulically the first chamber from the second chamber of the motor pump. Further, in order for this type of motor pump to operate well, the rotor must be centralized with respect to the stator, so as to prevent contact between them.

However, depending on the use of the motor pump, there is the consequent wear of the above-mentioned devices, which causes these motor pumps to lose mechanical efficiency, besides bringing maintenance costs and change of parts.

Thus, patent PI0103034-5 B1 belonging to Eberle Equipamentos e Processos S.A. describes a simplified motor pump configuration. This patent describes a motor pump where various devices present on the motor pump described before were eliminated, such as the roller bearings, gaskets, axis and the external cooling system.

According to patent PI 01030340-5 B1, the motor pump exhibits a rotor with one of its ends being coupled to a turbine, forming an integral rotor/turbine assembly. Said assembly is perforated, defining a passage for fluid. In this way, when said motor pump is in operation, the fluid gets into the rotor/turbine assembly after passing through an inlet, reaches the turbine and is impelled toward an outlet.

However, a part of the fluid, instead of being led to the fluid outlet, circulates in the motor pump. This fluid that remains in the motor pump creates a fluid film. Thus, by the action of centripetal forces of the rotor/turbine assembly and by the hydrostatic forces of the fluid film, the assembly does not come into contact with the motor-pump walls, remains immersed in the fluid, providing a floating bearing.

Thus, the motor pump of patent PI0103034-5 B1 exhibits simpler manufacture and maintenance, besides being more silent than the ordinary motor pumps, due to the existence of a floating bearing which allows a lesser amount of parts for it assembly.

However, the motor pump as described above exhibits a flow-rate limit, since the fluid must go through a fluid passage defined by the rotor/turbine assembly. In this way, the passage diameter defines the limit of fluid that goes through the motor pump, and so there is a loss of fluid-flow, in addition to a loss of impulsion due to the path which the fluid should travel as far as the outlet of the motor pump.

Thus, the present invention has the objective of presenting a novel configuration of the motor pump, which eliminates the problem of flow-rate restriction of the motor pump described, keeping the circulation of fluid inside the motor pump, thus enabling the floating bearing. This new configuration provides an increase in the flow-rate inside the motor pump, causing the latter to have higher yield.

BRIEF DESCRIPTION OF THE INVENTION

The present invention relates to a motor pump comprising two chambers, the first one being isolated from fluids and the second one defining the fluid passage, with a fluid inlet and a fluid outlet.

The stator is located in the first chamber, which in a preferred embodiment is adjacent to the walls that separate the first chamber from the second chamber, so that the fluid that circulates through the second chamber can cool the stator by heat conduction.

In the second chamber are located a rotor and a turbine, that operate in conjunction, and which are located at least partly concentrically with respect to the stator. The rotor/turbine assembly is induced electromagnetically by the stator, so as to impel a fluid from the inlet to the outlet.

Upon operation of the motor pump, and since the inlet and the outlet are located at the same end of the motor pump (first end), a fluid guide, preferably of conical shape, is located at the front end of the rotor/turbine assembly. In this way, when the fluid is impelled into the motor pump, most of the fluid is guided directly to the fluid outlet, while the remaining part is kept inside the motor pump.

The portion of fluid that is kept inside the pump creates a fluid film around the rotor/turbine assembly. Thus, the centripetal forces generated by the assembly and the hydrostatic forces of said film enable the rotor/turbine assembly to turn with minimum friction, thus providing a floating bearing. Additionally, the fluid that remains inside the motor pump circulates around the first chamber, cooling the stator by heat conduction, thus eliminating the need from an external cooling system, since the heat exchange between the circulating fluid and the rotor/turbine assembly will cool this assembly, so that the temperature can always remain at desirable levels.

In view of the above, the motor pump of the present invention, when allow the change of the fluid flow inside the motor pump, provides an increase in the flow-rate in the motor pump, eliminating losses due to flow restriction, which enables the motor pump to exhibit greater yielding. Besides, the motor pump of this novel configuration keeps a floating bearing, with a simpler configuration and with lower manufacture cost, eliminating the use of external cooling systems (coolers), as well as roller bearings, axis and mechanical sealing.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will now be described in greater detail with reference to an example of embodiment represented in the drawings. The figures show:

FIG. 1: a cross-sectional side view of the fluid motor pump according to the present invention;

FIG. 2a : a cross-sectional side view of the rotor/turbine assembly of the fluid motor pump, showing a fluid guide;

FIG. 2b : a side view of the rotor/turbine assembly of the fluid motor pump, showing where it the cross section of FIG. 2 a;

FIG. 3a : a back side view of the rotor/turbine assembly showing the relief holes;

FIG. 3b : an orthogonal view of the rotor/turbine assembly;

FIG. 4: a cross-sectional view similar to that of FIG. 1, showing the fluid path inside the pump according to the teachings of the present invention;

FIG. 5: an exploded perspective view of the pump according to the present invention, which enables a clearer visualization of its components; and

FIG. 6: an external perspective view of the fluid motor pump in its preferred embodiment.

DETAILED DESCRIPTION OF THE FIGURES

FIG. 1 illustrates a preferred embodiment of the present invention, where one observes a motor pump 10, free from components that are usually found on this type of motor pump, such as roller bearings, external cooling system, axis and mechanical sealing. The present embodiment illustrates a motor pump 10 that comprises a housing 14, preferably made from an injected polymeric material or any other material suitable for the operation conditions of the motor pump 10, which comprises a first chamber 19, isolated from fluids, and a second chamber 17, which defines the fluid path inside the motor pump 10. Moreover, said motor pump 10 further comprises a fluid inlet 15 and a fluid outlet 16, which are located at a first end A of the motor pump 10.

In the second chamber 17, there is a solidarity rotor/turbine assembly 11, which allow the impulse of the fluids that pass through said chamber 17 when it is in rotation. This assembly 11 is bore-through, creating a fluid channel 18, and besides it is made from a polymeric material. Moreover, at the front end 24 (FIG. 2a ) of the assembly 1 there is a ring 21 for centrifuging fluid and inside this ring 21 there is still a fluid guide 20, preferably a conical one. In the housing 14 (FIG. 1), there is a first chamber 19, which is isolated from the fluids that circulate in the second chamber 17. In the first chamber 19, there is a stator 12, which induces, by means of a magnetic field, the actuation of the rotary movement of the rotor/turbine assembly 11.

Besides, the second chamber 17 of the motor pump 10 further comprises a plurality of fluid passages 17.1, so as to enable the fluid to circulate through it. Said fluid passages 17.1 further enable the fluid to circulate around the first chamber 19, cooling the stator 12 by heat conduction.

As can be seen from FIG. 2a and as already mentioned before, the rotor/turbine assembly 11 is composed by a ring 21 and a fluid guide 20. In this way, when in operation, the fluid, after passing through the inlet 15 of the chamber 17 (FIG. 1), comes in contact with the fluid guide 20 (FIG. 2a ), restricting the fluid enters in the fluid channel 18 of the rotor/turbine assembly 11, so that most of the fluid goes directly to the fluid outlet 16 (FIG. 1), due to the rotation forces of the rotor/turbine assembly 11, which impels the fluid with radial force toward the fluid outlet 16. Most of the fluid remains circulating inside the chamber 17 in the fluid passages 17.1.

The fluid that remains in the motor pump 10 (circulating fluid other than that led to the outlet 16), after circulating throughout the second chamber 17, goes through the passages 17.1 in opposite direction with respect to the inlet 15, gets into the rotor/turbine assembly 11 (as indicated by the arrows S), goes through a fluid channel 18, the inlet of which is located at a second end B of the motor pump. The fluid from the channel 18 follows toward at least one outlet 22 present at the front end 24 of the rotor/turbine assembly 11, reaches the ring 21, which is in rotary movement, being impelled toward the fluid outlet 16.

Moreover, when the remaining fluid is circulating in the second chamber 17 through the passages 17.1, it creates a constant fluid film 13 between the walls of the second chamber 17 and the rotor/turbine assembly 11. In this way, the centripetal forces of the rotor/turbine assembly, with the hydrostatic forces of the film 13, enable the assembly 11 to turn freely, without coming into contact with the walls of the second chamber 17, thus providing a floating bearing. Thereby, besides the fact that the film 13 serves as a support for the assembly 11, it also acts as a lubricating fluid, which virtually eliminates the friction between the assembly 111 and the walls of the second chamber 17.

However, although the rotor/turbine assembly 11 is kept in a position out of contact with the walls of the second chamber 17, by said hydrostatic pressure of the film 13, it is the magnetic field emitted by the stator 12 that chiefly keeps the assembly 11 in a balance position around its axis, through the generated electric magnetic force E. However, the electromagnetic force E alone is not sufficient to keep the assembly 11 in a balance position, since the entry of fluid into the motor pump 10 causes a suction force D contrary to the electromagnetic force E, which tends to displace the assembly 11 toward the fluid inlet 15. In this way, for the axial balance of the assembly 11 be kept, the ring 21 has, at its rear part, at least one relief hole 23, as shown in FIGS. 3a and 3b . In a preferred embodiment five relief holes 23 are employed, radially equidistant. Through each of these relief holes 23 a fluid flow is created, which brings about a relief force F (axial thrust), contrary to the suction force D, which helps the electromagnetic force E, emitted by the stator 12, to keep the rotor/turbine assembly 11 in axial balance.

In light of the above, it is noted that the chamber 17 has passages 17.1 enabling the fluid to circulate inside the motor pump 10, thus eliminating the need to use lubricating fluids and external cooling systems. Moreover, since the motor pump is composed almost entirely of an injectable polymeric material, there is a reduction of components with respect to the usually known motor pumps, which makes its simplest and most economical to assembly.

Thus, the motor pump of the present invention, by virtue of the embodiment described, exhibits minimum loss of energy, since the fluid circulating inside the motor pump 10 creates a fluid film between the rotor/turbine assembly 11 and the second chamber 17, and the hydrostatic forces and the centripetal forces of the assembly 11 enable the assembly 11 to float (floating bearing), thus reducing friction of said assembly 11 with the walls of the second chamber 17.

Besides, with the fluid inlet 15 and fluid outlet 16 located at the same end A of the motor pump 10, this enables most of the fluid that goes into it to be impelled toward the outlet 16 practically at the same moment when it enters, without there being loss of force to impel the fluid. Also, there is no loss of fluid-flow due to restriction of the diameter, since the area available for passage of the fluid is substantially constant, enabling an increase in the fluid flow inside the pump and, as a result, causing the motor pump to exhibit greater yield. It should be pointed out that in the prior art there is the need for the main fluid to pass throughout the fluid channel 18, which has a reduced area section (there is substantial loss of load), as compared with the area through which the main flow of the invention in question flows.

Moreover, it is important to point out that the space existing between the stator and the rotor is known in the prior art as a gap and is filled with air, while in the present invention this space, besides being filled by a fluid film 13, there is a polymeric layer in the second chamber 17 and in the rotor/turbine assembly 11 and still there are relief holes 23. The combination of the film 13, the polymeric wall and the relief holes 23 guarantees perfect centralization of the stator 12 and of the assembly 11, as well as a balance position thereof around the axis, so that when the assembly 11 in operation makes a rotational movement the contact of the assembly 11 with the walls of the second chamber 17 is prevented.

Finally, it is also important to point out that the motor pump 10 of the present invention is corrosion-proof, since only the surface made from polymeric materials and Series AISI 304 stainless steel will contact the fluid. Moreover, since the motor pump of the present invention uses the circulating fluid itself for cooling, it can be installed at places without ventilation or submerged places.

A preferred example of embodiment having been described, one should understand that the scope of the present invention embraces other possible variations, being limited only by the contents of the accompanying claims, which include the possible equivalents.

LIST OF REFERENCE NUMBERS

10—motor pump

11—rotor/turbine assembly

12—stator

13—fluid film

14—housing

15—fluid inlet

16—fluid outlet

17—second chamber

17.1—fluid passage

18—fluid channel

19—first chamber

20—fluid guide

21—ring

22—outlet bores

23—relief holes

24—front end

A—first end

B—second end

S—fluid path 

1. Floating-bearing motor pump (10), cooled by a circulating fluid, which comprises a housing (14) formed by: a first chamber (19) isolated from fluid, which comprises a stator (12); a second chamber (17) that is in fluid communication with a fluid inlet (15) and a fluid outlet (16) and that comprises fluid passages (17.1) and a rotor having a turbine coupled at its front end, forming a solidarity rotor/turbine assembly (11); wherein the rotor/turbine assembly (11) is bored-through, forming a fluid channel (18); and wherein said fluid outlet (16) is orthogonal to a front end (24) of the rotor/turbine assembly (11); characterized in that the fluid inlet (15) and the fluid outlet (16) are located at a first end (A) of the motor pump (10); and the rotor/turbine assembly (11) comprises, fixed at its front end (24), a fluid guide (20) with at least one outlet bore (22).
 2. The floating-bearing motor pump (10) cooled by a circulating fluid, according to claim 1, characterized in that the fluid guide (20) has a conical shape.
 3. The floating-bearing motor pump (10) cooled by a circulating fluid according to any one of the preceding claims, characterized in that the fluid guide (20) restricts the entry of the fluid coming from the fluid inlet (15) in the fluid channel (18) of the rotor/turbine assembly (11).
 4. The floating-bearing motor pump (10) cooled by a circulating fluid, according to any one of the preceding claims, characterized in that the entrance of the fluid channel (18) is located at a second end (B) of the motor pump (10).
 5. The floating-bearing motor pump (10) cooled by a circulating fluid according to any one of the preceding claims, characterized in that the fluid passages (17.1) form a constant fluid film (13).
 6. The floating-bearing motor pump (10) cooled by a circulating fluid according to any one of the preceding claims, characterized in that the fluid passages (17.1) further enable the fluid to circulate around the first chamber (19) isolated from fluid, cooling the stator (12).
 7. The floating-bearing motor pump (10) cooled by a circulating fluid according to any one of the preceding claims, characterized in that the rotor/turbine assembly (11) is composed by a ring (21) to centrifuge fluid.
 8. The floating-bearing motor pump (10) cooled by a circulating fluid according to claim 7, characterized in that the rear part of the ring (21) comprises at least one relief hole (23).
 9. The floating-bearing motor pump (10) cooled by a circulating fluid according to claim 8, characterized in that the rear part of the ring (21) comprises five relief holes (23).
 10. The floating-bearing motor pump (10) cooled by a circulating fluid according to any one of the preceding claims, characterized in that the area available for passage of fluid to be carried is substantially constant.
 11. The floating-bearing motor pump (10) cooled by a circulating fluid according to claim 9, characterized in that the loss of fluid transport load is minimal, by virtue of the restriction in the area through which the fluid circulates.
 12. The floating-bearing motor pump (10) cooled by a circulating fluid according to any one of the preceding claims, characterized in that the space between said rotor/turbine assembly (11) and the stator (12) is filled by the walls of the first (19) and second (17) chambers.
 13. The floating-bearing motor pump (10) cooled by a circulating fluid according to any one of the preceding claims, characterized in that the housing (14) is made from an injectable polymeric material. 